Download Respiratory System Notes 2014

BIOL&242 / Anatomy & Physiology II
G. Brady / SFCC / 2014
Chapter 23 Notes
HUMAN RESPIRATORY SYSTEM
Upper Respiratory System =
1. Nose
2. Nasal cavity
3. Paranasal sinuses
4. Pharynx (throat)
Lower Respiratory System =
1. Larynx (voicebox)
2. Trachea (windpipe)
3. Lungs
4. Bronchi
5. Bronchioles
6. Alveoli
Primary Respiratory System Functions:
1. Supply oxygen to cells
2. Eliminate CO2
(Failure = death of cells due to:
1. oxygen starvation
2. buildup of waste products)
PATH OF AIR FLOW:
1. Nose = external nares (nostrils)
(stratified squamous & olfactory mucous membrane)
2. Nasal conchae = superior, middle, and inferior
turbinates.
(ciliated pseudostratified columnar epithelium, CPCE);
(CPCE also contains goblet cells throughout most of the
respiratory tract)
3. Pharynx = nasopharynx, oropharynx and laryngopharynx
(CPCE)
4. Glottis = true vocal cords and the space between them
which is called the rima glottidis.
(CPCE)
5. Larynx (voicebox) = connects the pharynx with the
trachea.
(CPCE)
The larynx contains the epiglottis and the following
cartilages:
a) thyroid cartilage (Adam's apple)
b) cricoid cartilage (connects the larynx and trachea)
c) paired (2 each of the following):
Arytenoid cartilage
Corniculate cartilage
Cuneiform cartilage
6. Trachea (windpipe) = has "C"-shaped rings of hyaline
cartilage, smooth muscle and is lined with CPCE.
The trachea extends from the larynx to the primary bronchi.
7. Primary bronchi*
8. Secondary bronchi*
9. Tertiary bronchi*
*walls of bronchi contain cartilage.
bronchi is CPCE.
10. Bronchioles = NO cartilage.
muscle. Inside lining is CPCE.
Inside lining of
Walls contain smooth
11. Terminal bronchioles = same as bronchioles only
smaller. (branch of bronchiole)
12. Respiratory bronchioles = branch of terminal
bronchiole. Lined with simple cuboidal epithelium.
NONCILIATED, so debris particles at this level of the
respiratory system are removed by macrophages.
13. Alveolar Ducts = subdivision of respiratory bronchiole
that terminates in alveolar sacs.
Lined with Simple Squamous Epithelial cells (SSEC).
14. Alveolar sacs = resemble clusters of grapes.
Lined with SSEC.
15. Alveoli = tiny, balloon-like expansions along the
alveolar sacs.
Lined with SSEC.
The walls in alveoli consist of:
a) Type I alveolar cells = simple squamous pulmonary
epthelial cells (where CO2/O2 exchange takes place in
lungs).
b) Type II alveolar cells (also called septal cells) = they
have microvilli and secrete alveolar fluid which keeps
alveolar cells moist and also contains surfactant which
lowers the surface tension and prevents collapse of alveoli
during exhalation.
c) alveolar macrophages (dust cells) = cell that is
phagocytic for dust, debris and foreign invaders found in
lung alveoli.
LUNGS:
Enclosed and protected by the pleural membrane in the
thoracic cavity. The right lung has three lobes, separated
by two fissures (horizontal and oblique fissures).
The left lung has two lobes separated by the oblique
fissure. The superior lobe of the left lung contains a
depression called the cardiac notch.
The thoracic cavity is lined with parietal pleura (outer
layer).
Visceral pleura (serous membrane or serosa)is the inner
layer that covers the lungs themselves.
Pleural cavity = small space between the visceral pleura
and parietal pleura that contains fluid to reduce friction
between the two membranes.
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BREATHING AND pH:
Increase rate and depth of breathing for 1-3 minutes = more
CO2 exhaled = increase in pH (more alkaline).
Decrease rate and depth of breathing for 1-3 minutes = less
CO2 exhaled = decrease in pH (more acid).
Note: pH of body fluids affects the rate of breathing.
Exhaling CO2 by increasing the rate and depth of breathing
causes reduction in the carbonic acid levels in the blood.
This raises blood pH by reducing H+ (hydrogen ion) levels.
Acidosis = pH < 7.35, results in depression of CNS synaptic
transmission and may lead to coma and death.
Alkalosis = pH > 7.45, results in over excitability of CNS
and over facilitation of synaptic transmission.
Compensation = physiologic response to an acid base
imbalance.
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RESPIRATION (3 Steps):
1. Pulmonary Ventilation = breathing. Air flows in and out
of the lungs by inhalation and expiration.
2. External Respiration = exchange of gases (O2/CO2) in the
lungs. Pulmonary capillaries pick up oxygen and eliminate
CO2.
O2 and CO2 move by diffusion.
O2 moves from:
Type I alveolar cells
To
Epithelial basement membrane
Then out into
Interstitial space
Then to
Capillary basement membrane
Then through
Capillary endothelium
To
Red Blood Cells inside the capillaries.
CO2 moves from:
Red blood cells inside capillaries
Through
Capillary endothelium
Then across
Basement membrane
Into
Interstitial space
Then to
Epithelial basement membrane
Into
Type I alveolar cells
And exhaled by lungs.
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Note: O2 and CO2 are moving by diffusion through the same
structures, just in opposite directions.
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(last of the 3 steps of respiration):
3. Internal Respiration = exchange of gases (O2/CO2)
between blood capillaries and tissue cells of the body.
Red blood cells lose O2 and pick up CO2 at the tissue
level.
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HEMOGLOBIN =
1. Heme = pigment molecule that contains four atoms of iron
(fe), each capable of combining with a molecule of oxygen.
2. Globin = large, globular protein.
Relationship between temperature and oxygen saturation of
hemoglobin:
Lower temperature = increased oxygen saturation of
hemoglobin.
Higher temperature = decreased oxygen saturation.
Affects of pH on oxygen affinity of hemoglobin:
High blood pH (eg. pH 7.6) = increased affinity of
hemoglobin for oxygen.
Low blood pH (eg. pH 7.2) = decreased affinity of
hemoglobin for oxygen.
Affects of PO2 on oxygen affinity of hemoglobin:
Low blood PO2 = decreased affinity of hemoglobin for
oxygen.
High blood PO2 = increased affinity of hemoglobin for
oxygen.
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PULMONARY VENTILATION = breathing.
1. Inspiration (inhalation) = diaphragm contracts (moves
downward). External intercostal muscles also contract.
This results in INCREASED size of the chest cavity,
decreasing intrapleural pressure and lungs expand.
Lung expansion decreases alveolar pressure and air moves
from the outside atmosphere into the lungs.
2. Expiraton (exhalation) = occurs when alveolar pressure
is HIGHER than atmospheric pressure.
Diaphragm and external intercostal muscles relax.
Lung volume decreases, alveolar pressure increases, and air
moves from the lungs to the outside atmosphere.
Note: internal intercostals and abdominal muscles are used
during FORCED exhalation.
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CONTROL OF RESPIRATION:
The respiratory center in the brain is the:
1. medullary rhythmicity center in the medulla oblongata
controls the basic rhythm of respiration.
2. pneumotaxic area in upper pons limits inspiration and
facilitates expiration to prevent over expansion of the
lungs.
3. apneustic area in the inferior pons prolongs inspiration
and inhibits expiration.
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Hering-Breuer Inflation Reflex = detects lung expansion
with stretch receptors to prevent lung damage by over
expansion.
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GAS LAWS:
Boyle's law = The volume of a gas varies INVERSELY with
pressure.
Dalton's law = In a mixture, each gas exerts its own
pressure as if all the other gases were not present.
Henry's law = The quantity of dissolved gas in a liquid is
proportional to the partial pressure of the gas and its
solubility (when temperature is constant).
The higher the partial pressure of a gas over a liquid and
the higher the solubility, the more gas will stay in
solution.
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***KNOW THE FOLLOWING***:
LUNG VOLUMES / CAPACITIES:
Tidal Volume (TV) = volume of one normal breath in or one
normal breath out = 500 mls.
Minute Respiratory Ventilation (MRV) = respiratory rate
multiplied by the tidal volume.
Eg. 12 breaths per minute X 500 mls = 6,000 mls MRV.
Inspiratory Reserve Volume (IRV) = volume of air which can
be taken in as a deep breath after normal tidal volume
inspiration.
Normal IRV = 3100 mls
Expiratory Reserve Volume (ERV) = volume of air which can
be exhaled after inhaling a normal tidal volume (TV) and
then exhaling forcibly.
Eg. 1700 mls - 500 mls = 1200 mls ERV.
Inspiratory capacity = TV (500mls) + IRV (3100mls) = 3600
mls.
Vital capacity = IRV (3100) + TV (500) + ERV (1200) = 4800
mls.
Total Lung capacity = IRV + TV + ERV + Residual volume =
about 6,000 mls (normal).
Residual volume (RV) = The amount of air that remains in
the lungs AFTER forced expiration = 1200 mls.
(Note: Residual volume cannot be measured using the
spirometer).
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ACID / BASE BALANCE:
Maintaining homeostatic pH levels in body fluids depends
on:
1. Buffer systems that bind H+ such as:
a) protein buffer system
b) bicarbonate buffer system
c) phosphate buffer system
2. Exhaling CO2 (by changing rate and depth of breathing).
3. Kidney excretion of H+
Respiratory Alkalosis = decreased PCO2, increased pH.
Cause: hyperventilation
Metabolic Alkalosis = increased HCO3-, increased pH.
Cause: excessive vomiting or taking alkaline drugs such as
Mylanta.
Respiratory Acidosis = increased PCO2, decreased pH.
Cause: hypoventilation (eg. holding breath).
Metabolic Acidosis = decreased HCO3-, decreased pH.
Cause: loss of bicarbonate ions or failure of the kidney to
excrete H+.
NOTE:
Respiratory Acidosis / Alkalosis is a disorder of blood
PCO2.
Metabolic Acidosis / Alkalosis is a disorder of bicarbonate
ion (HCO3-) concentration.
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PULMONARY BLOOD FLOW:
Pulmonary veins carry OXYGENATED blood to the heart.
(colored red on models to indicate oxygen in the blood
vessel).
Pulmonary arteries carry DEOXYGENATED blood away from the
heart to the lungs. (colored blue on models).
NOTE:
In the systemic circulation:
Veins carry deoxygenated blood (blue) TO the heart.
Arteries carry oxygenated blood (red) AWAY from the heart.
Veins are vessels that carry blood TO the heart and
Arteries are vessels that carry blood away from the heart.
Not all arteries carry oxygenated blood (exceptions are the
pulmonary arteries and the umbilical arteries), and not all
veins carry deoxygenated blood (exceptions are the
pulmonary veins and the umbilical vein).
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BREATHING PATTERNS:
Diaphragmatic breathing = deep abdominal breathing
Costal breathing = shallow chest breathing using external
intercostal muscles
Eupnea = normal, quiet breathing
Hyperpnea = forced breathing; accessory muscles assist with
inhalation. Exhalation involves internal intercostals and
abdominal muscles.
Apnea = breath holding
Dyspnea = painful breathing
Tachypnea = rapid breathing
(Modified Respiratory Movements: coughing, sneezing,
sighing, yawning, sobbing, crying, laughing, hiccuping,
valsalva maneuver.)
Hiccuping = spasmodic contraction of the diaphragm
Cheyne-Stokes respiration = irregular breathing pattern
seen just before death
Anoxia = (without oxygen). Oxygen to the tissues is cut
off and cells quickly die. May be caused by circulatory
problems, respiratory problems or cardiovascular problems.
Asthma = chronic inflammatory disorder that produces
narrowing of the airways
Bronchiogenic carcinoma = common lung cancer.
as pleuropulmonary neoplasm.
Also known
Bronchitis = inflammation of the bronchi characterized by
hypertrophy and hyperplasia of glands and goblet cells
lining the bronchial airways
Atelectasis = incomplete expansion of the lung or portion
of the lung
Emphysema = disease in which alveolar walls disintegrate
producing large air spaces that remain filled with air
during expiration
Cystic fibrosis = inherited disease involving secretory
epithelia
Epistaxis = nose bleed
Hemoptysis = "spitting" up blood from the respiratory tract
Pneumonia = acute infection of alveoli (most common
infectious cause of death in the U.S.)
Pulmonary embolism = blockage of a branch of a pulmonary
artery resulting in interruption of blood flow to a group
of lobules and/or alveoli.
Rales = rattling sound in the lungs
Rhinitis = inflammed mucous membrane in the nose
Tuberculosis = communicable infectious respiratory disease
caused by Mycobacterium tuberculosis. (1 in 3 people
worldwide are infected; kills 3 million people per year).
Pulmonary edema = abnormal accumulation of interstitial
fluid in alveoli
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Hypoxia = deficiency of oxygen (O2) at the tissue level.
FOUR TYPES:
1. Hypoxic hypoxia = low PO2 in arterial blood
eg. high altitude, airway obstruction, fluid in the lungs.
2. Anemic hypoxia = insufficient hemoglobin
eg. hemorrhage, anemia, carbon monoxide poisoning.
3.Ischemic hypoxia = blood FLOW to tissue is reduced while
PO2 and oxyhemoglobin levels are normal
eg. atherosclerosis (blockage in blood vessels).
4. Histotoxic hypoxia = toxic agent blocks use of O2 by
tissue
eg. cyanide poisoning.
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THE END!
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